Electrochemistry

Which of the following substances conducts electricity in both the solid and liquid states?

• silicon dioxide

• potassium chloride

• potassium

• sulfur

Molten lead(II) bromide is able to conduct electricity due to the presence of __________.

• free atoms

• molten lead

• mobile ions

• bromine gas

Which of the following solutions would produce hydrogen gas at the cathode upon electrolysis?

1. 1. dilute nitric acid

2. 2. aqueous potassium hydroxide

3. 3. aqueous sodium chloride

• 1 only

• 1 and 2

• 2 and 3

• all of the above

Tin can be obtained by the electrolysis of its molten chloride.

The properties of the metal and its chloride are as follows:

• The metal forms as a solid

  above the molten chloride.

• The metal forms as a solid

  below the molten chloride.

• The metal forms as a liquid

  above the molten chloride.

• The metal forms as a liquid

  below the molten chloride.

Which of the following set-ups would have no change in the concentration of the electrolyte upon electrolysis?     

• Electrolyte: CuSO₄(aq)

  Electrodes: carbon

• Electrolyte: CuSO₄(aq)

  Electrodes: platinum

• Electrolyte: CuCl₂(aq)

  Electrodes: copper

• Electrolyte: CuCl₂(aq)

  Electrodes: carbon

Copper(II) sulfate solution is electrolysed using carbon electrodes.

Which half-equation represents the reaction at the cathode?

A spoon to be silver-plated is made the cathode in an electrolytic cell. Which of the following could be used as the anode and the electrolyte?

• Anode - Carbon

  Electrolyte - HCl(aq)

• Anode - Carbon

  Electrolyte - AgNO₃(aq)

• Anode - Silver

  Electrolyte - HCl(aq)

• Anode - Silver

  Electrolyte - AgNO₃(aq)

A sample of copper was purified by electrolysis.

The loss in mass of the anode was 40 g and

the gain in mass of the cathode was 36 g.

What is the percentage purity of this sample of copper?

• 10%

• 80%

• 90%

• 100%

In a simple cell, electrical energy is produced as a result of __________.

• a more reactive metal releasing electrons

• a less reactive metal releasing electrons

• ionic bonds being broken

• positive and negative ions coming together

Which pair of metals will produce the greatest voltage in a simple cell?

• Iron and copper

• Zinc and copper

• Calcium and magnesium       

• Lead and copper